


If You Love Me (let me go)

by joliemariella



Category: Undertale
Genre: Cheating, F/M, Inspired by Tyranttortoise, Soul Magic, Soulmates, Underfell, Underfell Sans
Language: English
Status: Completed
Published: 2017-08-01
Updated: 2017-08-01
Packaged: 2018-12-09 18:32:11
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 10,111
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11674740
Author URL: https://archiveofourown.org/users/joliemariella/pseuds/joliemariella
Summary: (Underfell AU) Sans goes to Grillby's for a few drinks on a Saturday night and finds it far more packed than he's accustomed to. It's there that he meets his soulmate, someone with whom his soul resonates so perfectly that everything else just drops away until it's just the two of them staring at one another from across a crowded room. Just the two of them moving in perfect harmony on the dance floor. Just the two of them in a broom closet at the back of the bar fumbling for contact and kissing like it's the first and last time...Unfortunately, Sans' soulmate isn't you.





	If You Love Me (let me go)

**Author's Note:**

> So this is a one-shot I wrote as a sort of expansion on something [tyranttortoise](https://tyranttortoise.tumblr.com/) over on Tumblr wrote in response to this prompt:
> 
>   _*You discover that there's such a thing as monster soulmates, someone with such a strong soul resonance with someone else, that there's practically a magnetic pull._  
>  _Every monster has one. And you're currently dating a skeleton monster._  
>  _However, he's never told you that you're his soulmate._  
>  _One day, you turn to your significant other and ask him the burning question on your mind:_  
>  _"Are we soulmates?"_
> 
> She wrote a bit for several of the original and AU skelebros, but it was the one she did for Underfell Sans that really intrigued me and made me want to expand on it XD You can read her original post [here](https://tyranttortoise.tumblr.com/post/163544488163/so-this-is-something-i-kinda-wanna-put-into-my-own)!
> 
> Story is SansxReader with a heavy focus on SansxOC. Smut towards the middle!

_'Cause these words are knives that often leave scars_  
_The fear of falling apart_  
_And truth be told, I never was yours_  
_The fear, the fear of falling apart..._

 

Grillby's is packed to the gills, more so than Sans has seen it in ages, and he doesn't think it's just the newly repaired jukebox bringing everyone in. It's not until he's on his fifth beer that the reason occurs to him; Saturdays are normally spent in with _you_ , watching movies and relaxing (and making out) on your couch. Tonight, however, you agreed to cover a late shift for a friend at work, which leaves your boyfriend free on a Saturday for the first time in a long time.

His friend's bar isn't usually one known for its dance scene, but apparently no one told that to the mob packing the floor tonight. It's so bad that the tables have all been pushed back out of the way to accommodate, which would normally bother Grillby, Sans knows, but he's doing such good custom behind the bar that the monster seems content to let it be.

Sans is toying with the idea of making his way out to the dance floor as he leans against the bar, red eyes scanning the crowd. He's not about to go out there alone, though, and he's trying to decide if you'd be upset with him for dancing with some other girl while you're at work. It's just dancing, right? Nothin' wrong with a little dancing; didn't mean he wanted to hook up or anything. Granted, there isn't anything 'just' about the way people are moving out on the floor right now... He can practically smell the cloud of pheromones coming off the crowd, enhanced by the salt scent of sweat as the temperature continues to climb, the deafening pulse of music managing to stir something feral and lusting in even the shyest wallflowers.

He wishes you were here to dance. You haven't been dancing in ages thanks to your work schedule, and you're generally too tired on your days off to even consider it. Maybe he needs to work on you, convince you to go out anyways because watching these other humans and monsters seek one another out and make their way onto the dance floor is killing him. He takes a deep breath and almost regrets it as the rich, organic smell of so many bodies moving in unison to one intensely erotic, driving, evolutionary _need_ to fuck and drink and move as one being with a single purpose fills his senses and stirs the same in him.

Yeah, okay, he needs to leave.

Sans is pushing his way through the crowded bar along the edge of the even more crowded dance floor when he sees her. She's seated at a table along the far wall with a group of humans, and when his eyes land on her back, it's as though the world stops, dropping out from under his boots and leaving them the only two people in all the world. She feels it too, he _knows_ she does deep down in his soul as it cries out to hers, silently begging this stranger to turn and look, see him, meet him, _love him..._

She turns, brow furrowed in confusion, hand on her chest and color high as her eyes search the crowd for whatever is stirring this disquiet in the depths of her being.

Objectively, Sans knows you're more beautiful than her; the girl who's stolen his breath away is pretty in an average kind of way, but certainly not the type that stands out in a crowded bar full of girls dressed in their clubbing best. In that moment though, he couldn't recall your face, familiar and dear to him as it is, if he tried. But he's not trying. All he can think of is her, how he wishes his body would _move_ so he could grab her attention, go to her, something, _anything._

And then, miracle of miracles, her eyes find his across the crowd and Sans feels the wind rush out of him all in one ragged, shaking breath, and it's like seeing color for the first time. Her eyes go wide as she too feels the bond snap into place and the whole world comes into focus. She fumbles her way out of her chair, nearly tripping in the process, her drink and friends forgotten despite their calling after her as she starts towards the strange monster staring at her from across the dance floor.

The bottle of beer he's been nursing slips from Sans' hand and bounces off the toe of his boot, then rolls away across the floor, spilling its contents and nearly causing several people to slip. He pays their angry cries no mind as he too starts forward, pushing his way through the mob of dancers, craning his head as he strives to keep the stranger (his other half, his reason for being, his _soulmate_ ) in view as she threatens to disappear in their midst. Then there's a fortuitous shift in the crowd and she's there in front of him, breathless and a little rumpled from her struggle, but prettier than a picture in his eyes. They stand there, staring at one another as they try to catch their breath, neither quite sure what to say now that they're here.

"i-" Sans begins, voice raised to be heard over the blair of the music, but there's another shift in the dancers around them, totally ignorant of the magnitude of what has just happened in their midst, and the woman is knocked forward with a yelp. Without a second thought, Sans steps forward and grabs her, steadying her as he brings her into the protective circle of his arms, and the feel of her there is so _right_ he thinks his soul might go supernova and take the whole bar with it. He can't imagine having ever held anyone else the way he holds her in that moment, nor of holding anyone else ever again. She was made to be there; he was made to hold her and the proof comes in the perfect, blissful way she fits against his body.

She turns her face up to look at him and Sans can't for the life of him remember what he was going to say in that moment before he grabbed her. If he had a heart, it would have stopped at the wide-eyed, wondrous way she stares at him now as she reaches up and brushes the fingers of one hand along the hard line of his jaw. Her touch is electric and he struggles to remember how to breathe when her hand comes to rest at the nape of his neck.

The woman's brow furrows quizzically, eyes narrowed in a hopeful sort of bewilderment as she finally speaks.

"Do I… Do I _know_ you?" she asks, and though her voice is in no way audible over the powerful thump of the music that surges around them, Sans can hear her just fine. Not physically but… it seems to the monster he can feel her every word echo through his soul in a voice that he's always known.

It's an exquisite kind of pain that threatens to render him mute, but he forces himself to speak all the same. "yes," he answers immediately, then shakes himself a little in an attempt to clear his head, though it's no good. It's too full of her. "no," Sans admits, and the little bemused smile that curves her lips as she watches him fumble threatens to break his soul in two for the sheer joy of looking on it for the first time. The skeleton reaches up and cups her cheek with one hand as he keeps the other pressed solidly against the small of her back, and the warm, silk feel of her skin under his palm sparks a powerful need in him that makes breathing difficult and thinking even more so.

"no," he repeats, and his eyes burn down into hers with an intensity that would frighten most, but only seems to draw her deeper into his embrace. "but my soul knows yours," Sans says, quiet enough for his words to be lost in the music, though he knows without a shadow of a doubt that she can understand him just fine as he leans in until his forehead touches hers. Her eyes drift shut and she takes a deep, shuddering breath as he continues. "my soul would know yours across a thousand years and a hundred lifetimes," the monster tells her as they begin to move to the music that has so completely caught up the other couples on the floor finally, and he knows in the marrow of his bones just how true that statement is.

How easily he'd snubbed fate when you asked him about soulmates two months before. He'd been so flippant when he'd said he wasn't about to let the universe tell him who to be with, but here, now… he knows he's been an arrogant fool. How was he supposed to deny this? To deny _her_? His soul flutters in his chest and he can feel hers do the same, the sweet, harmonious push-pull of soul magic between them leaving him with the head spinning realization that he knew both everything and nothing about the woman in his arms.

He doesn't know her name, but Sans knows her soul is perfect foil to his own. He tends towards sloth when left alone, but she knocks heads and takes names until the job is done to her satisfaction. She is prone to jumping in head first, a counter to his own more patient nature; and they're both kind at heart. Many people have told Sans as much, though he's always played it off awkwardly or covered his embarrassment with some callous comment in an attempt to convince them otherwise. Here in his moment, though, he can't deny that fact, not when he sees himself so perfectly reflected in her.

Her eyes are searching his, and he wonders to what extent she feels all of this; does she realize what a perfect match they are? That she's his other half, and he's hers? Does she know he'd die for her despite having only just met her? Conquer the world for her? He'd spend the rest of eternity alone in the Underground for the undeserved bliss of a single day spent in her company, he thinks, and is momentarily startled by just how true the thought rings.

The woman's brow furrows and she opens her mouth to speak, but hesitates and closes it before dropping her forehead to rest against his shoulder. "I don't even know your name," she whispers.

"sans," he tells her without hesitation.

"Sans," she repeats, and a shiver runs up the length of his spine at the sound of his name on her lips. Before he even has to ask, she introduces herself. "I'm Sam."

"Sam," he breathes, enjoying the way her name feels rolling off his tongue. It seems to the monster that he's always known it, as if her name had been engraved on his soul at the time of its making and he had only forgotten it for a little while.

She trembles in his arms and he tightens his hold on her. "Why do you feel so right?" Sam asks, turning heavily lidded eyes up to regard him once more as she shifts her hold so both her arms are around his neck now, allowing her to move in time with his steps.

Sans' hands drift to her hips, breath catching in his chest at the brush of her body against his as she presses in close. Her lips are just slightly parted, and his tongue flicks out across the sharp points of his teeth in response to the sight.

"because we're soulmates, sweetheart, didn't i say?" he teases, light headed as her hands drift down to the flat plane of his chest and she chuckles.

"Pretty sure someone's used that line on me before," she remarks and he's entranced as she turns so her back is to him, hips swaying enticingly in time to the music.

"it's not a line," he growls as he presses up behind her, hips digging into hers and making her gasp when he runs his hands down the length of her before sweeping them across the flat of her belly to drag her back against him. Her back winds up against his chest and he grazes his teeth along the column of her throat, soul jumping with longing when she actually tilts her head and exposes that swath of untouched skin for him. He can see the way the little hairs their stand on end as his breath tickles her, and he experiences an overwhelming compulsion to sink his teeth into her tender flesh, to mark her as _his_ for all to see. It's not something he's ever felt before, though he knows the practice is common among those rare few who manage to find their soulmate. He'd always just assumed it was some kinky shit people were into, he'd never realized it was such a visceral need they experienced. He barely manages to resist, the certain knowledge that him biting the woman in his arms here and now would result in a panic among the humans around them managing to worm its way into his compromised thinking long enough to save him from a mistake that would likely end with the police showing up.

"i know you feel this too," he murmurs into her ear instead, his hands slipping up under the hem of her shirt even as her skirt rides up dangerously when she rolls her hips torturously against his rapidly developing hard on. He feels her breath catch and the small moan that escapes her almost proves his undoing.

They're caught up in the heavy press of bodies on the dance floor, part of the many becoming more and more carried away by the increasingly erotic atmosphere filling the bar. On a normal night Sans might wonder if Grillby hadn't been slipping something into everyone's drinks for things to take such a turn in the normally sedate establishment, but now all he can think of is the woman dancing so enticingly before him, tempting him headlong into the sort of heedless sensuality he's rarely experienced. He's always been a flirt, confident in his ability to charm, but this is something else entirely...

The beat is hot and fast, and it's not long before they're both swept up into that particular brand of dionysian madness that drives all thought of past or future from the mind in favor of the sensory overload that is the present where alcohol burns through the veins and breath comes rapid and labored while one's blood pounds in time with the music. There's nothing for Sans but that hypnotic beat and his soulmate's touch as she grinds against him, driving him mad as she pushes aside his coat and hoodie to shove her hands up under his shirt. The heat of her hands over his ribs makes the monster's arousal spike and he grabs her hips again, unashamedly allowing his own hands to sweep down over the curve of her backside and take hold. Only the thought of other men's eyes on her keeps him from dragging her skirt up then and there, though the sensation of her hand palming him through his jeans gives him second thoughts.

He gasps her name and she meets his eyes. What he sees there makes him moan outright and and close the last few scant inches of distance between them just as she pushes up to do the same. Her lips crash against his teeth and he wastes no time slipping his tongue into her mouth right there in the middle of the dance floor. She tilts her head back and lets him in willingly, her moan sending an electric shock right up Sans' spine and encouraging him to deepen the kiss, exploring her feverishly, tasting her for the first time, memorizing every detail. His hands go up to cup her face, and when he finally breaks their kiss, he opens his eyes in time to see her long lashes flutter as she gasps for breath.

"No," she growls and throws her arms around his neck, bringing her lips to his teeth again. "More," she pleads desperately. "Sans, I-I need-" she gasps, and that's all it takes to send the monster over the edge.

Sans wraps his arms around her and spins away into darkness, teleporting them away from the floor and into the back hallway of the bar, the first place that came to mind that affords a little peace and quiet away from the main crush of humanity in the main area. The woman is grinding mercilessly against him, one leg kicked up over his hip as she presses desperate kisses along his jaw and cervical vertebrae, rendering it nigh impossible for him to think straight. There's a broom closet there, and Sans yanks the door open without hesitation then carries her inside, bearing her full weight easily as he catches her mouth with his once more.

It's dark and musty inside, but neither of them notices as he shoves her up against the back wall and she lifts her other leg so she's wrapped around his hips and riding him like a woman possessed.

"fuck, babe please," he begs as he shoves her skirt up around her waist and struggles to pull her underwear down while he buries his face in her neck and she rakes her painted nails across the vertebrae at the base of his skull. She whimpers desperately and the noise makes Sans give up playing nice and he rips the little strip of fabric right off her like so much tissue paper, making her gasp and throw her head back so it bumps the wall, exposing the curve of her breasts to his tender mercies. He drags down her top and bra and latches onto her left breast, drawing a ragged breath from her when his sharpened teeth graze her areola, only for his tongue to follow immediately after, assuaging any fleeting hurt he might have inflicted on her in his excitement.

She's soft, she's so fucking _soft_ in his mouth, under his hands, grinding against his hips; he needs to know if she's just as soft on the inside. As though his soulmate read his mind, she slows the unforgiving roll of her hips and drops a little to fumble with his belt while he steadies her, one hand clamped firmly on her ass and the other pressed against the wall behind her. She has it undone in a trice, then slips her hand within to push down his boxers and grasp his cock, making him gasp at the feel of her hand wrapped around his length.

"Red," Sam muses aloud, more than a little breathless herself, making him open eyes he hadn't even realized he'd closed. She's examining him and he doesn't even have a chance to wonder if she's put off by his magically constructed anatomy before she's stroking him and his knees are threatening to buckle. She leans in and runs her tongue along the line of his jaw, then purrs, "Can I call you 'Red', baby?"

"sweetheart, you can call me whatever you want so long as you keep that up," he rasps, voice rough as Sam works him, pad of her thumb sweeping across the head of his cock, leaving it slick with magical precum. He groans and swears as he watches her lift the digit to her mouth and suck it clean, and he knows he can't wait anymore.

Sans lifts her, then drops her back down again, slamming into her with force enough to make her cry out and cling to him with legs and arms both. He shoves her against the back wall with a dull thud, both hands gripping her hips hard enough to bruise as he fucks her hard and fast, his pace merciless as she writhes around him. It's their first time and he's not kind about it; there is no gentleness to be found in this desperate, dirty secret of a hook up that should mean nothing but means _everything_ to both of them.

Sam takes him to the hilt like a champ, and meets Sans thrust for thrust after the initial shock of his onslaught, riding him energetically, breasts bouncing with the force of their movements. His soulmate is breathing hard, and he's falling more in love with her with every passing moment as she keeps pace, then pushes him harder, demanding more until he's on the edge, senses overwhelmed by the scent of her, the wet, maddening heat of her wrapped around his cock. Sam tightens convulsively and he knows she's almost there too, and the only thing bothering him as he buries his face in her shoulder is the lingering scent of another man.

He'd noticed it before on the dance floor, but he'd ignored it. What did another guy matter in the face of what they had? What did anyone mean? There was only them. Sam was his and he was hers and everyone else could burn for all he cared in that moment. Still, he ran his tongue up her throat, then across her breasts, wiping away what traces of the other man lingered on her even after their dancing.

She was his. He'd scream it from the fucking rooftops if he had to. He'd fill her up, obliterating all hold that other male had on her, and he'd mark her to show the world just who she belonged to.

"you're mine," he growls aloud, teeth grazing her shoulder. "say it," he demands as he lifts his head to meet her eyes, his gaze burning fierce and crimson into hers as he keeps up the brutal pace they've set.

Sam's eyes threaten to roll back in her head when he hits her sweet spot, and she moans when he adjusts his angle to lean over her more to keep it up, still supporting her weight with ease as he fucks her within an inch of her sanity. "Y-Yours," she gasps and struggles to meet his eyes but finally manages. She looks wrecked; make-up smeared and hair loosed from its careful coif, and he loves it; revels in it. "I'm yours, Sans."

"good. oh damn, sammy sweetheart, you're good," he hisses as she tightens around him further and he clenches his jaw, breathing harsh as he continues, "mine, no one else's."

"Yours, only yours," she repeats and tilts her head to the side in silent invitation. The monster's eyes flash and he lunges in, not needing to be told twice as he buries his teeth in the soft skin of her shoulder.

His soulmate claps a hand over her mouth to silence her own scream as the agony of his bite sends her cascading over the edge into a powerful orgasm that rocks her to the core. The convulsive fluttering of her walls around his cock is enough to make him release his grip on Sam's shoulder and throw his head back with a cry as he thrusts into her once, twice, and then a final time as he empties himself into her. Sans' eyes fly open wide when, while that sweetly intoxicating cascade of magic is filling her, Sam leans forward and bites down hard on his clavicle, drawing a strangled shout from the monster.

When she releases him, they sag back and fight to catch their breaths. She's shaking, brushing her hair back from her face with an unsteady hand until he leans in, and with all the gentleness he'd lacked during their lovemaking, cleans her wound with his tongue. When he's done, Sam glances down, and her eyes go wide when she sees not an open lesion, but a shiny, silvery scar that looks as though it's been there for years.

His soulmate looks up at him, eyes wide with wonder, and Sans actually flushes a little at the awe and adoration in her gaze. Sam's gaze drifts down to where she bit him in turn, and the way her eyebrows shoot up in surprise makes him crane his head a little to glance down as well. He blinks, shocked, when he realizes that she's not the only one with a new scar. Her teeth have left sharp, white marks in the mellow ivory of his clavicle, which should have been impossible. Monsters are fragile, but it took more than a love bite to leave a mark on _his_ bones.

Their eyes meet again, and he just smirks. Just as he's about to open his mouth and make a smart comment, though, there's a banging on the door that makes them both jump and panic. She drops off his hips, dragging him free of her with a gasp. He struggles to get his pants buckled and Sam gets her skirt pulled down from around her waist, though there's no saving her tattered underwear, which she kicks out of sight behind a bucket just as the door crashes in.

There's a group of five women there, and it becomes apparent that these are his soulmate's friends judging by the way they're shouting at her for disappearing, and screaming at _him_ for taking her, all while threatening to call the cops. Sans' head is spinning with the speed of it all, and before he can get a word in edgewise, the women are sweeping _his_ Sam away down the hall. Just before she disappears from sight, though, she turns and points at him as she silently mouths, ' _Mine_ '.

Sans' soul lets out a joyous pulse at the sight, and when she's gone, he sags weakly against the doorframe of the closet and shakily works to put himself back into some real semblance of order. He didn't get her phone number, but he's not worried. In that moment, as he makes for the backdoor and exits just in time to see a car pull out of the parking lot, Sans knows he'll search to the ends of the earth to find her again. No one, human, monster, or god himself, will keep her from him.

* * *

Sam has been bundled into the back of that same car by her friends, and is immediately inundated with questions.

"Holy shit, girl, what happened back there?" asks May, the woman in the driver's side back seat, concern writ clear on her features as she leans around Emily, who is squished in the center spot, to try and get a look at her friend's face.

"Who the hell _was_ that guy?" asks Skye from the front passenger seat, completely flabbergasted by the unexpected turn their evening took.

"Are you okay?" Emily asks gently when Sam continues silent. This prompts all five friends, including the driver (though only briefly) to crane around and look at her.

"Hmm?" Sam asks, voice dreamy, as though she hasn't heard a single word. She's been staring out the window, still completely wrapped up in her own little world and the connection she's forged with Sans. The soul bond is a steady, warm presence just behind her breast bone and her hand goes to the spot absently as she smiles. Her shoulder is sore where he bit her, but pleasantly so. After their activities in the bar closet she knows that's likely not the only place she'll be aching tomorrow, but in that moment she couldn't possibly care less. If anything, she looks forward to the reminder it will serve as that this hasn't all been an impossibly wonderful dream...

"Shit, you don't think he roofied her or something, do you?" the driver, Kerri, asks with a frown. "Sweetie, did your drink taste salty at all tonight?"

"She barely even touched it before she went off with that guy, and he never came near the table." the Skye comments skeptically.

"Could have been the bartender," May suggests with a dark frown, arms crossed over her chest.

"What?" Sam asks, reality finally manage to break through her fugue of bliss. "No one _roofied_ me guys, oh my god." Her eyes go to her friend that suggested the bartender as a suspect and she says, "Sans didn't drug me, and neither did the bartender."

"Sans? So you _do_ know that skeleton guy?" Emily asks curiously from her spot directly next to their friend. She's by far the calmest about the situation, which surprises Sam a little. Of the six of them, Em is the only one that's really 'settled down'; husband, kids, career, the whole nine yards. Honestly, even getting her out with them that night had proved to be something of a miracle. On the other hand, the woman had never been easily flustered, so maybe the fact that she had the 'tamest' life of the lot of them shouldn't mean she can't take unusual situations well in stride.

Hell, maybe she was the best qualified.

Sam blinks as Emily regards her steadily, waiting for her answer. "Well, I know him _now,_ " the woman mumbles, flushing crimson under the weight of her friends' stares.

"Well I should say so," May huffs, trying hard not to grin and failing miserably.

"Right?!" Skye exclaims from the front seat. "Cuz, real talk for a sec', guys... Sam, did you seriously just hook up with a skeleton man _in a broom closet at the back of a bar?!_ "

"That's sure as hell what it looked like to me," Kerri drawls, though her reflection in the rear view mirror looks almost proud.

"I-I, um..." Sam stutters, her blush intensifying before she gives up and covers her face with her hands in defeat and squeaks out a quiet 'yes'.

"Holy shit."

"But how would he even-"

"Damn, girl, get it! Sammy got mad monster game!"

"No, but legit, how would that even work? Does he have a dick, or like, is he just _really_ good at going down?"

All eyes turn back to Sam again who feels ready to take a dive out the passenger door, moving vehicle or no. "No, he um... he had one. It was... magic?"

The staring continues.

"Liiiiiike, metaphorically magic?" Skye asks, bemused. "Or like, _literally_ magic?"

Sam manages to pry her hands from her face at the memory and that dreamy expression returns to her face as she heaves a breathy sigh. " _Both,_ guys. Both."

Kerri lets out a low whistle of appreciation. "That uh- that good, huh?" she asks, taken aback by her friend's wistfulness. Emily had always been the one with the solid gold good-girl rep in their group (she'd married her high school sweetheart for goodness sake), but Sam hadn't been far behind. She'd always been a go-getter when it came to just about anything _except_ her love life, so finding her hooking up with a monster guy in a closet was a shock to say the least.

Sam fans herself a little and laughs, "I mean... I know I don't have a super long list of guys to pull from but, yeah. He was... incredible."

"Well, damn, now you're just making me jealous," Skye complains without any real heat, a smile tugging at her lips.

Everyone laughs but Emily, who kills the air of good humor with a single question. "What about Jason?"

"Huh?" Sam asks with a blink as she turns to regard her friend. The woman doesn't seem upset, just concerned, a frown furrowing her brow.

"Jason?" Emily repeats hesitantly, glancing around at the other girls as they all come down as well, smiles slipping. "You know... your boyfriend?"

The b-word is enough to finally break through Sam's utter bliss, shattering that sense of joy and contentment that had stayed with her since the moment she laid eyes on Sans across the dance floor.

"Oh, hell, I forgot you were still seeing that guy," Kerri mutters with a grimace.

They've all met Jason a couple of times, though he hasn't exactly been 'brought into the fold' by the girls yet. She's been seeing him for a little over a year now, Sam remembers abruptly, they'd just gotten a place together two months ago. She feels a sharp twinge of guilt for completely forgetting his existence, but then she's rocked by the memory of Sans' hands on her hips, her mouth on his, how impossibly _right_ it'd felt when he'd first taken her in his arms, and she knows she never stood a chance.

The way Sans says her name makes her toes curl, and the tenor of his voice is as familiar to her now after only an hour in his company as the melody of her favorite song. Sitting there in the backseat of Kerri's car, she's struggling to even remember what color Jason's eyes are. Green? Hazel? All she can imagine in their stead is a pair of glowing red irises that cut through her every facade to see into her very soul, a part of her she's never even been truly _aware_ of until tonight. Even so far removed from Sans she can still feel it burning hot and bright as a star behind her breast, and knows that the gentle ache at its core is all for him.

"He's my soulmate," she murmurs aloud without meaning too, her expression gone wistful once more as she gazes out the window unseeing.

Skye's nose crinkles at her words. "Who, Jason? I mean, he's a nice guy, but that seems to be coming on a bit strong, hon."

"What? No," Sam says with a grimace of her own at the idea. "I... I meant Sans."

This proclamation is also met with silence until May finally offers, "Er... I know the dick was great and all, Sammy, but that's a bit much too, don't you think?"

They don't understand, and Sam folds in on herself a little, soul aching in her chest. "I know it sounds silly," she says eventually, and her friends share a look among themselves as she continues, "But I... But I mean it _literally._ The moment I lay eyes on him there was this-" Sam gestures vaguely, completely at a loss on how to possibly describe the sensation that had irrevocably changed the course of her entire life fromt hat night on. "I don't know, a connection. A bond deeper than I've ever felt with _anyone._ And when he told me his name? It was like I'd always known it and I'd been waiting my entire life just to hear his voice."

The girls stare, and eventually Skye leans over to Kerri and murmurs, "I know we ruled out roofies, but is mind control a thing monsters can do?"

Sam flinches and Kerri punches Skye hard in the arm with a scowl. "No, it is _not_ something they can do, asshole," the driver says sharply.

"Ow! No need to get violent, just thought I'd ask," the other woman grumbles while May rolls her eyes.

"Soulmate, though? Is that really a thing for monsters?"

"It is," Emily says, surprising everyone with the confidence in her words. She blushes a little when they all stare at her. "W-What?" she stammers a little defensively. "You know I like to read!" Everyone's expression softens a little bit in the face of this familiar truth. Emily wasn't just the good girl of the group, she was also their walking, talking google. She knew a little bit about everything, so if she said it was so, they were all inclined to believe her. Relaxing a little, her frown returns as she looks at Sam once more and repeats her earlier question. "So, what about Jason, then? If this Sans person really is your soulmate..."

"Pretty big jump to make," May adds. "I mean, you've been with Jason for like a year now, right? Do you love him? You guys just got a place together, you willing to ditch all that for some guy you literally just met and hooked up with at a bar?"

The question stings, but Sam knows it's not an unreasonable one. She's not _that_ far gone. The woman sighs and leans against Emily, who allows her friend the use of her shoulder and even pets her hair in a soothing fashion. "I..." she begins, but is cut off by Kerri.

"Look, not like you've gotta decide tonight, right?" she points out as she glances from the road to where she can see Sam in her rearview mirror.

"Well, she did just kinda cheat on Jason," Skye points out apologetically, but quiets when Kerri holds up a threatening fist again.

"I know, and I'm normally super against that sort of crap," Kerri says, and everyone knows this is true as well. Her first husband had cheated on her, and it hadn't been a pretty recovery from that broken trust, though she's dated a few guys since. "But we'll call meeting your literal magical goddamn _soulmate_ an exception to the rule, okay?" She shoots a look at the occupants of the car, and everyone but Sam nods. "Just... think about it a few days before you decide on anything, huh? Go home, take a good look at the man you've got, and then decide if the new one's worth leaving him over."

Finally, Sam nods and smiles weakly around at her friends, glad for their company in that moment, even if they couldn't possibly comprehend what has passed this night. She certainly couldn't have when she'd left her apartment for a night out with the girls just a few hours ago.

"Yeah, I'll just... I'll play it by ear for a change."

"That's my girl."

* * *

Sans is standing on a street corner lighting up a cigarette when reality finally comes crashing in around his head and the magnitude of what has happened, and what he's done, finally hits him.

"shit," he whispers, cigarette hanging limply between his teeth with his lighter hovering halfway to its end. The flame flickers out in a passing breeze and Sans frowns, relighting it with a deft flick and finishing what he started. When his cigarette catches, he clicks the lighter shut and tucks it back into the inside pocket of his trench and takes a long pull. Smoke gushes from his nose and between his sharpened teeth as he repeats himself.

"shit."

He fucked up. He fucked up bad.

Thoughts of Sam swirl to the surface of his mind as he starts walking again and he smiles boyishly at the memory of her smile, the soft curve of her lashes, the way she'd ridden him like a prized pony in that cramped broom closet at the back of Grillby's bar...

He fucked up _great._

A soulmate? Him? It sounds like a bad joke where the only punchline should be a fist in the gut, but it isn't. Not this time. No, for the first time in Sans' life, something good, something _fucking perfect_ has come his way and he'll be damned if he doesn't reach out and take it.

He'd sooner die.

All those years in the Underground struggling to survive, fighting to save not only his own (metaphorical) skin, but Papyrus' as well, in a kill or be killed society of monsters driven to desperation by circumstances wholly out of their own control... and now he has a chance at something greater. He'd thought finally seeing the light of day was his reward for so many patient years spent simply surviving, rather than truly living, but maybe it wasn't. Maybe coming to the surface had only been a stepping stone to meeting her. Sam. _His Sam._

His exultation softens a little at the thought of his soulmate. He can't take her for granted, he knows; he can still fuck this up irreparably, and the very thought of losing her makes him nauseous. These bonds weren't a guarantee, especially so early in the relationship, and if there's anyone that could mess up something so wonderfully perfect, drive away the most beautiful soul to ever walk the face of the Earth, it would sure as hell be him.

Terror gnaws at the pit of Sans' gut as he comes to a stop at the foot of the stairs up to his front porch, unable to move a step further in the face of the fears that have descended to plague him.

Finally, though, he growls and shakes them off before taking a long drag of his cigarette and exhaling the smoke in one long, harsh woosh. Fuck that, and fuck all the doubts trying to drag him down. He'll never forgive himself if he doesn't _try,_ so try he will. He'll woo her, make her love him for more than just the resonance of their souls so she'll never want to leave him, and they'll be happy. He'll learn everything there is to know about her by heart, day by day as he gradually uncovers all her secrets because they've only just met... but he loves her.

He loves Sam and the thought of a life without her makes him want to lay down and give up right there on the sidewalk in front of his house.

Sans finishes his cigarette and practically springs up the steps to his front door, stubbing the remains out in the ashtray he leaves on the railing for just that purpose, then lets himself in. He takes two steps inside and then stops, suddenly overwhelmed by the scent of you lingering in the entryway. You'd only just been there a few hours before, and normally he loves coming home to the familiar smell of your perfume, but tonight...

Tonight it's jarring to senses that long only for the scent of a woman who is not you, and douses his excitement like a bucket of water over a flame.

Sans hovers in his doorway as thoughts of you swarm his mind, paining him with certain knowledge of what he's going to have to do. You don't live here, though you might as well. In fact, he's been working up to asking you to move in for some time, but now...

One of your hoodies is hanging on a hook by the door, and a pair of your flip flops are pushed into a corner by the door where you left them a few days prior. You have a toothbrush here, and an entire drawer of the rarely used dresser in his room all to yourself.

The skeleton hesitates, then takes a step backwards and shuts the door again and locks it. He can't face the traces of you that linger in his home, not tonight. He knows that hurting you is inevitable, and it pains him to think of it, but the alternative feels like a death sentence.

He crashes at Papyrus' place instead.

* * *

It's Wednesday and you're becoming increasingly worried by the way Sans has been acting since you had to cancel movie night a few days before. He hasn't been distant, per say, but something feels distinctly _off,_ though you can't quite put your finger on how. You tell yourself he didn't hesitate to kiss you Sunday afternoon when you visited, and that your lovemaking hadn't been unusually perfunctory later that night. He still smiles at you, still teases and flirts, but it's as though a fire has gone out behind his eyes and that terrifies you.

It's when you go through the motions of getting ready to go back to your place that night and he doesn't try to stop you like he normally would that you _know_ something is up. Unless he has literally passed out on the sofa, Sans always tries to get you to stay the night, generally via out and out seduction, though sometimes through sweeter means. Tonight, however, he sees you to the door and waves you off with a kiss and a smile, and you struggle to act normal, like this isn't completely bizarre and out of character for him to do.

You should call him out on it, confront him, but paranoia stops you and sends you to your car without a single objection. You don't want to be the crazy girlfriend that suspects your boyfriend of infidelity just because he's having an off week, not when you've been together for so long with nothing but mutual trust and understanding between you.

That doesn't stop you from parking your car down a shadowed side street and waiting until you see him leave his front door ten minutes later and set off at a brisk walk. Your heart beats frantically and tears threaten at the corners of your eyes as you watch him turn the corner, dark trench billowing around him in the evening breeze. You follow at a distance in your car, and it doesn't take you long to realize he's heading to Grillby's. You feel a little stupid as you park your car down the road a bit where you have an unfettered view of the bar and tell yourself you're being crazy. So what if your boyfriend wants to go for a drink at his favorite bar without you for a change? There's nothing wrong with that.

Except that it's totally out of character for Sans.

You sit in your car debating on what to do now, not daring to go inside. There's no way he wouldn't recognize you; you're still wearing the exact same outfit for goodness sake, and what were you supposed to say then? You going to Grillby's without plans to meet him there is even stranger than him going without you. At least he has the excuse of being close friends with the monster that owns the place...

Maybe that's it? Maybe he just wanted to see Grillby?

Or maybe he was cheating on you with Grillby.

The thought makes you wrinkle your nose at the absurdity. No, the fireman definitely isn't your boyfriend's type, but that doesn't mean he's not meeting someone else...

It's a slow night for the bar, though, and besides a few couples that all arrive and leave together during the four hours you sit and watch, no one of note arrives. You're almost dozing off when Sans finally leaves. Whatever he was hoping to accomplish that night, your boyfriend doesn't look terribly pleased as he makes his way back to his apartment. He lights up a cigarette as he goes, and you watch the smoke trail after the skeleton and linger on the air even after he vanishes from sight.

You don't tail him back to his place, but go home instead, still at a loss and wondering if you're going crazy.

The next night you're supposed to work, but you call in sick and show up to Sans' with a plan. It's already after dark and he's not expecting you. In fact, it's after the hour he left for Grillby's the night previous, and you know where you're going if he doesn't answer the door.

Your heart drops when Sans doesn't answer at your knock, hating to have your own suspicion confirmed. Still, you have a plan of action, so you drive to the bar for the second night in a row and park down the block where Sans won't see your car when he eventually leaves. Then, you pull on a wig you picked up earlier in the day, and a beanie over that. You finish off the look with a pair of thick rimmed glasses and take a moment to gather yourself before heading inside.

There's more people today than there were last night, but it's a Thursday so there's hardly a crowd. You enter and head directly for one of the corner booths once you note that Sans is seated at the bar. It's out of his direct line of sight, so you feel some extra modicum of safety from detection. A waitress arrives and takes your drink order, and you settle in to wait.

Sans is drinking alone, sipping absently from a glass of what you know from experience is bourbon while he reads something on his phone.

Hours pass without anyone but the wait staff so much as glancing as Sans, let alone walking up and... you don't know... seducing him? No one even talks to him, and you're glad you thought to bring a book.

Just like the night before, however, nothing happens, and Sans leaves without talking to anyone but Grillby and a couple of the waitresses when they take his order for a burger and fries partway through the evening.

You give him a good ten minutes to get down the road, then leave yourself.

It's wash, rinse, and repeat for the next few nights, and it's a battle to keep up the facade that everything is normal when you spend time with your boyfriend by day. Saturday he pleads sick and cancels you coming over altogether after work, though he seems just fine when you follow him to the bar a few hours later. It's much busier that night, but you find a corner to hide and drink in where you can keep an eye on Sans. Every other night he's ignored the room at his back, but that night he keeps turning back to the dance floor, though you're not sure if he's just intrigued by the dancers, or if he's looking for someone specific.

By Sunday you're wondering if your boyfriend hasn't just developed an alcohol problem and is trying (badly) to hide it from you by doing his drinking at a bar instead of keeping bottles around his place. You're starting to feel guilty as you pick over a basket of fries, wondering if you shouldn't be planning an intervention instead of stalking Sans to the bar every night to watch him drown himself in bourbon.

Grillby makes the last call and you watch with a pang as Sans drops his face into his hands, shoulders heaving with an exhausted sigh that makes your heart hurt to witness. Your boyfriend drags his hands down his face, then reaches into his back pocket for his wallet and starts counting out bills to pay off that evening's tab. You're trying to wave down a waitress to do the same when Sans' shoulders suddenly go rigid and he sits bolt upright, every trace of fatigue suddenly gone as he turns so fast he nearly falls right off his bar stool.

His eyes are locked on the door, though you note with some confusion that there's no one there. Sans has caught himself mid-stumble with uncharacteristic clumsiness, and is straightening when a woman gingerly pushes the door open and peers inside.

Their eyes meet and they both freeze as your stomach drops out from within you. Sans looks like a statue as he stands there staring at the strange woman who has stepped inside and allowed the door to swing shut behind her. When she takes another step towards him, you see his shoulders lift and fall, as though he'd forgotten to breathe in that long moment that stretched between them and only just now remembered.

Now they're moving towards one another, completely ignorant of anything and everything around them as Sans says, "you came," in the same moment she breathes, "You're here."

They come to a stop a few feet shy of one another, and the expression of naked longing, hope, joy, and terror that takes over Sans' features as he looks down at this woman you've never seen before feels like a knife in the heart. It drives the air from your lungs and you feel your throat close as tears threaten at the corners of your eyes.

Somehow, though... somehow the expression on the woman's face is even worse.

She's looking at him like he's everything she's ever dreamed of; the answer to every question she's ever had in her life. She's looking at your boyfriend with a smile like the sunrise after the long, dark night, as though she can imagine no more welcome sight in all the world than his face. She's looking at him like an old friend, a long lost lover, her other half, _her soulmate._

They're reaching for one another now, hesitant, wondering, hoping...

There's the smash of glass breaking and you give a start as you realize you're on your feet and you've knocked your drink off the table in your hurry to escape the death of your own relationship.

Spell broken, both of them give a start and look around. Her brow is furrowed in concern, and Sans looks confused for a moment until he sees through your disguise and his eyes widen fractionally as the magnitude of the moment hits him. You grab your purse and hurry for the door, but he calls your name, and despite every nerve in your body screaming for you to leave, to run while you still have some shred of dignity remaining, you wait, unable to resist him even now.

"wait," he says, voice low and rough. "i can explain. i-" You watch as he turns to the other woman and murmurs something quiet that you cannot hear, then pulls out his phone.

He didn't even have her number, you realize abruptly as they hurriedly exchange information. He's been coming to the bar every night hoping to run into her again, desperate to see her while he begs off spending time with you.

You laugh, a horrible, broken sound, and spin on heel, then push your way through the doors without waiting for him to follow.

He does, though, and he catches up before you make it out of the parking lot, let alone all the way to your car. Sans grabs you by the arm, and there's a familiar twisting sensation as you both step into the void in unison, then back out into his living room.

"You said it'd never happen," you gasp tearfully as your control breaks and you drop onto the sofa, dragging off your wig and casting it aside. You bury your face in your hands and struggle not to sob. "You promised-"

"i never promised," he corrects you, voice soft but firm, and Sans' words take the knife that's already been thrust into your heart and give it a brutal twist. "i never promised anything."

He's still on his feet in front of you, standing between you and the tv, shoulders sagging with exhaustion and hands buried in the pockets of his trench coat. You hate the sorrow that lingers on his face when you finally look at him because you know what it means for you and him.

"You're breaking up with me," you say, voice deadpan as the tears roll freely down your cheeks, dripping from your chin and onto the carpet of his livingroom floor.

"sweetheart-"

"Don't call me that," you snap and drop your eyes to the ground, scowling, heart in agony at the thought of him calling his new soulmate his favorite nickname. She's already taking him from you, you don't want to share a pet name too.

Sans takes a long, deep breath and releases it just as slow before sitting down beside you on the couch. He knows better than to touch you now, and the foot of space between you feels like a mile. "you don't want me to stay, not now that i've found her," he tells you, his deep, familiar voice threatening to soothe the hurt and anger from you in spite of yourself. He's always been able to do that, and you hate him for it a little now.

You struggle to breathe, and though you know it's pointless, you ask, "But I love you. I thought you loved me too… can't that be enough?" You turn your eyes up to look at him, gaze pleading as you continue, "Can she really give you so much more than me? Can she love you more than me?"

He's trying and failing not to pity you; you can see it in his eyes and you feel sick to your stomach at the sight. Anger sparks in your chest and you push your way to your feet to pace restlessly. "When did you meet her?" you demand, movements sharp, brisk, and hostile as you spin to look at him.

Sans remains seated on the sofa where you left him, and though you know he normally bristles at such snappy demands, he's completely calm when he answers. "last saturday while you were covering that shift. i went down to grillb'z for a drink and saw her across the room. After that..." the skeleton shrugs helplessly and you fight down the urge to laugh hysterically at this news.

Your own helpful nature has wound up getting you screwed out of a boyfriend. If you'd just turned your friend down and stayed in with Sans like you always did on Saturdays…

You can't think about that or you know you'll break down again, so instead, you lash out like a wounded animal with a question you know you'll regret. "So, did you fuck her then?"

Sans doesn't flinch at your question, but his eyes do narrow fractionally, their lights flashing in the impenetrable shadows of his eye sockets. "yeah," he answers, and the ease with which he answers your cruelly meant question is like a slap to the face. "i ain't proud of it, but yeah i did." He pushes the envelope, countering your mean spiritedness with a dose of his own. "fucked her in the broom closet because because the bond had me so out of my damn head i couldn't even remember your name."

"Fuck you," you spit, furious and hurting at his words as fresh tears spill from your eyes. You're shaking, and even clenching your hands into fists can't hide this fact.

The monster stands at long last and takes a few steps towards you. There's nothing aggressive in his posture, though, so you hold your ground and stare him down. "you asked," he says flatly, and that pained expression returns. He regrets the words now, you can tell, but that doesn't stop him from continuing. "and that's why you don't want me to stay," Sans says, voice gentle again, though solemn as he meets your eyes steadily with his own. "she's… shit," he says with a sigh and scrapes the bones of his hand across his skull. "she's in me, in my _soul_ , and that's not somethin' i'll ever be able to forget or ignore. if i stay with you i'll be lookin' back over my shoulder for the rest of my life and i know myself well enough to honestly tell you - you'd never be able to trust me again."

The fury bleeds out of you, leaving you feeling empty, tired, and heartbroken. "Why," you whisper. "Why did this have to… I love you so much, Sans. I _love_ you."

"i know," he says, his voice as ragged as yours now, and you don't dare look at him. Instead, you press your face into your hands again, shoulders shaking with grief at the loss of what had been. He doesn't say he loved you too, and frankly you're glad. You're not sure you could take it.

His arms go around you and you lean into him reflexively as your shoulders heave. The sobs you've been fighting so valiantly to resist escape full force now and your hands turn to clutch desperately at the familiar fabric of his jacket as you bury your face in the collar of his hoodie.

The familiar scent of him makes your heart _hurt_ , and as you cry yourself dry you suspect his arms are the only thing keeping you from flying apart at the seams.

"i'm sorry," he murmurs. "god, i'm so sorry. i never thought i'd ever-"

"Please don't," you manage to choke out, and he falls silent.

He's no longer yours, but Sans is as kind as he's ever pretended not to be, and he doesn't rush you out, despite his discomfort. He takes you home eventually, and puts you to bed. When you wake up in the morning you find he's delivered your car from where you left it at the bar, which you appreciate until you see the box he's left in the passenger seat. It's full of everything you've ever kept at his place, and it's that, more than anything said or done the night before that convinces you it's really over.

**Author's Note:**

> I originally wrote this without giving Sans' soulmate a name, and it worked just fine right up until I decided I wanted to do that scene with her in the car and trying to write around not only her, but _five other women in the same vehicle_ without a name was requiring some olympic level verbal gymnastics so I just gave her a name XD Hopefully you guys don't mind!
> 
> Well, hope you guys enjoyed! I'm actually considering adding another chapter or two just kinda following up on how Sans and Sam wind up really getting together. Would anyone be interested? Might throw something with Papyrus in there as well, heh. Make sure to leave a review and let me know what you thought! Reviews 100% help me keep writing, so it's in your best interest, right? ;D Only takes a few seconds of your time, after all...


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